Perigeniculate arachnoid cysts and CSF fistulae of the fallopian canal:Histopathologic correlates of a rare clinical entity

Cerebrospinal fluid(CSF)fistulae originating from the fallopian canal of the facial nerve is hypothesized to arise due to atypical patterns of subarachnoid space extension into the geniculate ganglion or more distal regions along the intratemporal course of the facial nerve,but its pathogenesis remains poorly understood.Although a rare etiology of CSF fistulae of the temporal bone,there are significant clinical ramifications due to the risk of recurrent meningitis,difficulty in identifying the anatomic location of the CSF leak,and technical challenges associated with surgical repair.We present three clinical cases of arachnoid cysts within the geniculate fossa with or without CSF fistulization and provide histopathologic correlates of this rare clinical phenomenon from a human temporal bone collection.The pediatric and adult patients presented suggest differential pathophysiologic mechanisms associated with CSF fistulae.Temporal bone histology reveals atypical patterns of subarachnoid space extension in the fallopian canal that may underlie arachnoid cyst formation and overt CSF leak from the geniculate region.

Update on oral and oropharyngeal cancer staging-International perspectives

Squamous cell carcinoma of the oral cavity and oropharynx have been used synonymously and interchangeably in the world literature in the context of head and neck cancers.As the 21st century progresses,divergence between the two have become more evident,particularly due to evidence related to human papillomavirus-associated oropharyngeal squamous cell carcinoma.As such,the American Joint Committee on Cancer recently published the 8th edition Cancer Staging Manual,serving as a continued global resource to clinicians and researchers.Through changes in staging related to T and N clinical and pathologic classifications,the new system is expected to influence current management guidelines of these cancers that have distinct anatomic and etiopathogenic characteristics.This article aims to review such impactful changes in a time of critical transition of the staging of head and neck cancer and how these changes may affect clinicians and researchers worldwide.

Electrocochleoeraphy in cochlear implantation:Development,applications,and future directions

Electrocochleography(ECochG)is an electrophysiological technique that records electrical potentials generated by different components of the inner ear and peripheral cochlear nerve in response to acoustic stimulation.ECochG responses can be analyzed into(1)cochlear microphonics(CM),(2)auditory nerve neurophonics,(3)summating potential,and(4)compound action potential.Over the past few decades,there have been ongoing refinements in technique and updates in the understanding of recorded potentials.Historically,ECochG found its main application in the diagnostic evaluation of Meniere^disease(MD).However,in the last decade,the focus has shifted towards cochlear implantation(Cl).In patients with residual hearing after Cl,combined electric and acoustic stimulation has resulted in improved hearing and speech outcomes.Despite efforts to mitigate trauma during electrode insertion,hearing preservation rates vary after surgery.During implantation,real-time ECochG offers an opportunity to measure frequency specific CMs elicited from a localized region in the cochlea as the surgeon inserts the electrode array.In extracochlear ECochG recordings,the recording electrode can be placed on the promontory,the stapes,or the tympanic membrane.Intracochlear ECochG can be performed by inserting a recording electrode into the cochlea or by using one of the Cl electrodes as the recording electrode.The loss of intraoperative ECochG signal may indicate cochlear trauma from electrode insertion,but the association between intraoperative ECochG changes and cochlear trauma remains controversial.The ability to monitor cochlear trauma during Cl electrode placement holds promise to improve hearing preservation outcomes,modify surgical techniques,and change electrode design.The goal of this review is to provide a comprehensive overview of the electrophysiology and history of ECochG,discuss its recent applications in Cl,and explore the ongoing research in this expanding field.

Imaging and choosing the right patients for transoral endoscopic parathyroidectomy vestibular approach

Advances in imaging for preoperative localization have propelled the widespread adoption of minimally invasive/focused parathyroidectomy in primary hyperparathyroidism.Though it is performed through a relatively small incision,studies have shown that the presence of a neck scar increases attentional bias towards the neck resulting in compromised quality of life.Transoral endoscopic parathyroidectomy vestibular approach(TOEPVA)eliminates a neck scar.While indications for TOEPVA are the same as that of minimally invasive open parathyroidectomy,confident preoperative localization of the parathyroid with a surgeon performed ultrasound along with concordant localization with SPECT CT is an essential prerequisite before offering patients this approach for parathyroidectomy.Early data has demonstrated the feasibility and safety of this approach.